Printable sensors have been described as part of the printed organic electronics market and for screen printing on glass or plastic for windows, such as those described in WO 2007/082137. For example, it is possible to attach accelerometers to expensive equipment that is shock sensitive. However, there exists a need for a low-cost simple sensor for detecting exposure to various temperatures, UV light, and visible light.
For some materials such as medicines or foodstuffs, it is difficult for the druggist, the supermarket, or the consumer to know what conditions an item has been subjected to from the initial packaging to receipt and/or purchase of the item.
Currently, many labels contain a “best before date” to inform a retailer or consumer of the condition of an item. However, the expiration date often depends on the actual exposure history of the goods to environmental conditions, including temperature, light, or ultraviolet light to which the item has been exposed.